| Abstract: | For the past few years, we have been engagedin isolating and separating middle molecules (MMs)from biologic fluids of healthy persons and uremicpatients. Plasma or serum, ultrafiltrate, and peri-toneal outflow dialysate from uremic patients, as well as plasma from healthy subjects, were fractionat-ed by gel chromatography. Plasma or serum waspretreated with a 40 x l cm Sephadex G 50 columnor by CXA ultrafilter. Fractionation of MMs wasperformed on a 100 x I cm Sephadex G 15 column,eluted with NH.HCO:} buffer. UV absorbance wasmeasured at 206 nm, 225 nm, or both. All samples could be separated into about 10peaks according to elution volume. Peak 2 and peak3, corresponding to the elution volumes for vitaminB12 and oxytocin, were significantly higher in uremicthan healthy sera. These two peaks were regardedas the main fractions containing uremic MMs. MMs measurement was used to: a) evaluate theefficiency of various dialyzers and hemoperfusion,b) evaluate the efficacy of continuous ambulatoryperitoneal dialysis (CAPD) and hemodialysis (HD)in the removal of MMs, c) calculate the total quantity of MMs removed by CAPD, intermittent peri-toneal dialysis and ultrafiltration, and d) assess theefficacy of reused dialyzers. Subfractionation of MMs by thin layer fingerprints technic was carried out. Identification of theseparated substances is in progress. |
